In order to drive a light emitting device having a light emitting diode (LED), a separate light source apparatus provided with an LED driving circuit is required. That is, since related art illumination lamps directly receive alternating current (AC) power to be driven, a separate light source apparatus is unnecessary, but an LED has characteristics such that it is driven by direct current (DC) power. In general, in an LED device, AC power is rectified, and in order to convert a DC signal rectified from the AC power to have a required magnitude, a DC/DC converter is included in a light source apparatus. Thus, demand for a scheme for miniaturization of a light source apparatus and an improvement in power efficiency under the conditions described above has been increased.